Tunnel-form.



C. D. MoARTHUR.

TUNNEL FORM, ABPLIOATION FILED F314. 1910.

6 SHEETS-SHEET 1.

WITNESSES INVENTOR X/IMAZZM D MQARTHUR.

APPLIGATIGN 11.11?) FEB.4, 1910.

Patented D90.20,1910.

1 3 fi win 5 SHEETB-SHEET 3.

C. D. MQARTHUR.

TUNNEL FORM.

APPLICATION FILED PEBA, 1910.

Patented Dec. 20, 1910.

5 SHEETS-SHEET 4.

Iii-III,

INVENTOR \PHTNESS 5/,

C. D. MOARTHUR TUNNEL FORM.

APPLICATION FILED IEB.4, 1910. I w 979 5 Patenzeai Dec. 20, 91

5 anus-SHEET s \RHTNESSES INVEWTQJR VIII of Figure 6, and

UNITED SKIES PATENT CHARLES 1). MCARTH'UR, or PITTSBUB-G, PENNSYLVANIA, ASSIGNOR 'ro BLAW cor.-

LAPSIBLE STEEL CENTEEING' COMPANY.

POBA'IION OF NEW JERSEY.

orrrrrsnnne; PENNSYLVANIA, A con- TUNNEL-FOR1YL Specification of Letters Patent. Pgtgnted E 26;, 191%,

Application filed February 4, 1910. Serial No. 542,065.

To all whom it may concern: I H

Be it known that I, CHARLES D. Mo-

Anrnnn, a citizen of the United States, re-v siding at Pittsburg, in' the county of Alleprovision of a form in which its sections may be readily and conveniently released from the concrete and taken down one after the other for use in another position; the provision of a form in which the series of lagging plates lying behind a pair of ribs may be readlly released and removed by re-. moving only one of the ribs; the provision of an improved fastening means between the ribs and the ends of the lagging plates permitting an adjustment-of the plates vertioally on the ribs without removing the securing bolts; and the provision of an improved form of key plate whereby the concrete at the top of the form may be more easily and effectively applied than has been the case with the forms heretofore employed.

Certain embodiments of the invention are illustrated in the accompanying drawing wherein,

Figure 1 is an end view of'gthe orm in place in the excavation,

' F gure 2 is a section on the line II'II of Figure 1, v

Figure 3 is a section of an enlarged scale on the lines IIl-III of Figures 2 and 4. I Figure 4 is an enlarged plan view of the connecting means between the ends of the lagging plates andthe ribs, v

Figure 5 1s a section on the line V.V of Figure 4,

Figure 6 is an enlarged planview of the top of asection of the form showing the key lagging means in position,

Figure 7 is an end view of the structure of Figure 6, Y

Figure 8 is a section on the line VIII Figures 9, l0 and 11 are views corre sponding to those of Figures 6, 7 and 8, and illustrating a modified for f fastening. r

Briefly stated the form consists of a semencing with the bot positim by means of a series of transverse beams and the lagging is then applied comnn plates. Concrete is filled in behind these plates, and other plates are "hen positioned, and the process of filling in continued until all of the plates with the exception of the top ones are added After the concrete has set upon the lagging, the form may /'be readily taken down in sections by removing a rib at a time, and then releasing the lagging plates held by the next succeeding rib. and carrying the parts'thus disassembled to the front end of the form, and positioning-them for re-use. The invention relates primarily to the means for supporting the lagging plates behind the ribs so that they may be readily released and taken down without taking down both of the ribs upon which the plates are supported, to the means whereby the plates are adjnstably secured to'the ribs, and to the arrangement of the lagging means at the top of the arch whereby the last portion of the concrete applied overtbe form may be more readily and conveniently positioned and compacted.

Referring to the general arrangement of the form, as shown in Figures 1 and 2, the principal parts maybe briefly enumerated as follows. 1, 2 and 3 are'the ribs spaced apart any convenient distance, and comprising channel beams, the sectlons of which are secured detachably together by means of the plates 4c, 5 and 6; 7, S, 921ml 10 represent-a supporting framework deta'chably bolted to the ribs means or" the gusset plates illustrated in Figure l, which framework serves to maintain the ribs securely in position the arch or key lagging means, which is of;

a peculiarstructure and which will be hereinafter more fully described, and 13 are the stiffening angles which are riveted to the secured detachably and adjustably toth'e flanges of the channels is illustrated in' enlarged detail in Figures 3, 4, and Extending vertically along the back of the rib is what may be termed a bearing strip 14:,-

which bearing strip is riveted to the channel. The ends of the lagging plates back-of the rib are provided with vertical 'strips 15 which hear at their inner ends upon the strip 14. Angled clips 16 are riveted adjacent the edges of the lagging plates, and are provided with perforations for carrying the bolts 17. extending over the flanges of the channels, and carry nuts 19. The holes in the flanges through which the bolts pass are preferably square and the shanks of the bolts are squared to fit these holes, so that the bolts do not need to be held to prevent them from turning while the nuts are being tightened. The weakening of the rib flanges by perfo rations is thus avoided. The arrangement also provides a convenient means whereby the lagging plates may be adjusted longitu dinally of the beams any desired distance by simply loosening the nuts 19. The use of the bearing strips 1 1 is desirable, in that it is comparatively easy to pull the lagging plates longitudinally to release them from the channels without taking down the channels. This could not be dcne'so readily if the plates 15 hada bearing clear along the back of the channel, as the increased friction due to the larger bearing surface would render the lagging plates dilficult of longitudinal movement. The stiffening plates 15 prevent the lagging plates from bending in ward under the pressure of the concrete in v termediate the angles 16 and the bearing strip 14:. 1

From the foregoing it will be seen that the form may be readily disassembled by taking down one rib at a time, and that the lagging plates while supported at their other ends by the remaining channel can be readily slipped from undersuch channel without taking it down. The ribs can therefore be taken down with safety in succession without the danger of any. of the lagging plates accidentally falling, as the plates are always releasably supported at one end.

'A slightly modified arrangement forthe securing of-thelagging plates to the ribs is shown in Figures 9, 10 and 11. In this modified form of fastening the angle clips 16 are secured to the flanges ofthe channel by means of bolts 17 the holes through the flanges of the .channelbeing slightly elongated as indicated in Fig. 11 in order to permit of a slight adjustment of the lag- The bolts 17 have hooked ends 18' ging plates with respect to the channels.

Bearing plates 14 and stiffening plates 15 are provided in the same manner as in the form of'joint shown in Figs. 3, 1 and The key lagging means 12 constitutes an other feature ofmy invention, and is shown in enlarged detail views in Figs. 7 and 8. It 18 this 'key lagging means which is the last lagging applied to the form, and it is of course necessary to apply the concrete over the lagging from the ends of the plates instead-of over the horizontal edges as in the case of the other lagging plates. This is a diiiicult, matter to accomplish satisfactorily when the ribs are spaced apart a considerable distance, and my invention is designed to overcome this diiliculty, by reducing the distance through which it is necessary to position and compact the concrete longitudinally of the form. Vvith this object in view the key lagging is formed in two tapered sections 20 and 21 supported at their outer endsupon the channels 1 and 2 and at their side edges upon the angles 22 riveted to the edges of the lagging plates 11. An angle 23 is also secured. to the edges of the plate 20, which angle overlaps the end of the plate 21. In operation after the plates 11 have been covered with concrete,'tb e plate 20'is positioned and covered with concrete the operator working from the end thereof,'and

illustrated its use, what I claim as new and desire to secure by. Letters Patentis the fol lowing 1. In combination in a tunnel form, a se rles of SPtlCQdIlbS comprising channels having, inwardly directed flanges, bearing strips of less width than the channels secured to the outerfaces thereof, lagging plates having their end edges resting upon the bearing strips; and means for securing the plates detac'hably to the flanges of the channels.

2. In combination in a tunnel form, a series of spaced ribs comprising channels having inwardly directed flanges, bearing strips of less width than" the channels secured to the outer faces thereof, sheet metal lagging plates having their end edges inopposition aehind the bearing'strips, stiffening plates secured: to the end edges of the lagging plates and bearing upon the bearing strips, and means for securing the lagging plates detachably'to the flanges ofthe channels.

8. In combination in a tunnel form, aseries of spaced ribs comprising channels havmg inwardly directed flanges, bearing strips of less Width than the channels secured to the outer faces thereof: lagging plates having their end edges resting upon the bearing strips, and angle clips and bolts for securing the plates deta'chably to the flanges of the channels.

t. In combination in a tunnel form, a series of spaced ribs comprising channels having inwardly directed flanges, lagging plates having inwardly extending flanges abutting the flanges of the channels, bolts extending through the flanges on the lagging plates and provided ontheir inner endswith hooks engaging the flanges of thechannels and on their outer ends with screw threads, andnuts threaded on such screw threaded ends. i

5; In combination in a tunnel form, a series of spaced ribs comprising channels having inwardly directed flanges; hearing strips of less width than the channels sewith a hook engaging the other flange and at the other end provided with screw threads, and a nut threaded on the screw threaded end of the bolt.

7. In combination in a tunnel torm hav ing an arch, a pair of spaced ribs, a series of removable lagging plates extending from one rib to the other and supported at their ends thereby, andkey lagging means for the arch comprising a series pf plates placed end to end and thus combined extending from one rib to the next, the said plates being of a width suflicient to extend across the space remaining between lagging plates.

S. In combination in a tunnel form having an arch, a pair of spaced ribs, a series of removable lagging plates extending from one rib to the other and supported at their ends thereby, and key lagging means for the arch comprising a plurality of sections placed end to end and together extending from one rib to the other, and partially supported along their side edges from the adjacent lagging plates.

9. The combination with a pair of arched circumferential ribs, of a series of laggin plates extending from one rib to the other with their ends lying therebehind, and key lagging means. at the upperportion of the -with their ends lying therebehind, and

the last two arch and comprising a pair of sections chutting t their inner ends intermediate the ribs and. supported at their side edges from the adjacent lagging. plates:

10. The combination with a pair of arched circumferential ribs, of a series of lagging plates extending from one rib to the other Y lagging means at the upper portion of the arch and comprising a pair of sections abutas ting at their inner ends intermediate the .ribs and supported at their side edges upon the adjacent lagging plates and aththeir outer ends upon the ribs.

11. he combination with, a pair of arched circumferential ribs, of a series of lagging plates extending from one. rib o the other with theirends lying therebehi d, and key lagging means at the upper portion of the arch comprising a plurality of sections, each of a length less than the distance between the ribs, placed end to end andthus combined extending from one rib to the other and supported. at their side edges fromth adjacentlagging plates. t

12. The combination with a pair of arched circumferential ribs, of a series of? lagging plates extending from one rib to the other with their ends lying 'therebehind, stiffening strips'secured along and projecting out past the opposing edges of the top lagging plates, and closing means for the space between such: top lagging plates comprising a plurality'ot abutting lagging sections extending between the ribs and supported at their side edges upon the stiffening strips.

13. In combination in a. knock-down form, a supporting rib having a projecting flange, a lagging plat-e provided with a flange abutting the flange of the rib and having a per toration of angular cross section, a securing bolt fitting such perforation and. provided at one end 'with a hook engaging the flange of the supporting rib and at the other end provided with screwv threads, and" a nut threadedon the screw threaded end of the bolt.

14. The combination with a pair of arched circumferential ribs, of a series of lagging plates extending from one plate to the other with their ends lying therebehind, and key lagging means at the upper portion of the arch comprising a plurality of sectigns, each ofa length less than thedistancebetween the .ribs, placed end to end and thus combined extending from one rib to the other and having their end edges inclined toward each other and supported from the adjacent :i'mrujtedfi flanges to me flanges of the channel mprising; Emits threafiaed at their outer [1s Extending through the perforated chsm' nais and having hooked inner ends engaging 1e flanges 03'. the (311213111813 and nuts on the magma; 

